Measurement speed is a performance parameter of modern signal analyzers that influences measurement throughput when the analyzers are used in manufacturing facilities and other testing environments. Some modern signal analyzers have two alternative modes of operationxe2x80x94a swept mode and a Fast Fourier Transform (FFT) mode. Measurement speed in these analyzers depends on which of the operating modes is used to perform measurements and on other measurement settings, such as measurement frequency span and resolution bandwidth.
Dynamic range, another performance parameter of signal analyzers, determines the accuracy of the measurements performed by the analyzers and is also influenced by the operating mode that is used to perform the measurements. Higher dynamic range generally corresponds to higher measurement accuracy. While signal analyzers having dynamic range enhancing circuitry, such as that taught in U.S. Pat. No. 5,844,512, generally have higher dynamic range in the swept operating mode than in the FFT operating mode, the dynamic range also depends on other measurement settings of the analyzer.
Since dynamic range and measurement speed are both influenced by the operating mode of a signal analyzer, there is a need for a method of selecting between these alternative operating modes that enables tradeoffs between measurement speed and dynamic range to be optimized.
A mode selection method for signal analyzers having alternative swept and Fast Fourier Transform (FFT) modes of operation is constructed according to the preferred embodiment of the present invention. The method enables tradeoffs between measurement speed and dynamic range to be optimized in selecting between the swept operating mode and a FFT operating mode in response to inputs to a user interface associated with the signal analyzer. The method includes setting the signal analyzer to either a manual state or an automatic state according to a first input to the user interface. When the manual state is set, the analyzer is operated in either the swept operating mode or the FFT operating mode according to a second input to the user interface. When the automatic measurement state is set, a third input to the user interface determines whether measurement speed or dynamic range is optimized. Measurement speed is optimized according to a first optimization scheme and dynamic range is optimized according to a second optimization scheme.